package servlet;

import model.User;
import model.UserDao;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

@WebServlet("/login")
public class LoginServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.读取参数中的用户名和密码
        req.setCharacterEncoding("utf-8");
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        System.out.println("用户登录: username:" + username + " , password:" + password);
        // 验证参数
        if(username == null || username.length() == 0 || password == null || password.length() == 0) {
            resp.setContentType("text/html; charset=utf8");
            resp.getWriter().write("您输入的用户名或者密码为空");
            return;
        }
        //2.查询数据库, 看看这里的用户名或密码是否正确
        UserDao userDao = new UserDao();
        User user = userDao.getUserByName(username);
        if(user == null) {
            //用户不存在
            resp.setContentType("text/html; charset=utf8");
            resp.getWriter().write("您输入的用户名不正确");
            return;
        }
        if(!password.equals(user.getPasswrod())) {
            resp.setContentType("text/html; charset=utf8");
            resp.getWriter().write("您输入的密码不正确");
            return;
        }

        //创建会话
        HttpSession session = req.getSession(true);
        session.setAttribute("user", user);
        //4.跳转到主页
        resp.sendRedirect("blog_list.html");
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //通过这个方法, 来反馈当前用户的登录状态
        //一个简单的判定方式, 直接看会话是否存在
        //此处使用更严格的判定方式, 不仅要求会话要存在, 还要求会话中要保存 user 对象
        // 之所以这样设定, 也是为了后面实现 "退出登录" 功能的铺垫
        HttpSession session = req.getSession(false);
        if(session == null) {
            resp.setStatus(403);
            return;
        }
        User user = (User)session.getAttribute("user");
        if(user == null) {
            resp.setStatus(403);
            return;
        }

        //两个都存在
        resp.setStatus(200); //此处200不写也行, 默认是200
    }
}
